• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.86-86
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• 2011

첨단 공정이 필요한 반도체와 LCD, PDP, LED 등의 디스플레이 및 IT 부품을 제조하는데 필요한 장비의 고성능화와 작업환경의 고청정화에 따른 초고진공펌프의 수요 확대와 앞으로 전개될 한-미 FTA에 따른 시장 확대로 인해 크라이오펌프의 국산화가 시급한 실정이다. 고성능 크라이오펌프를 만들기 위해서는 냉각판을 극저온으로 냉각하기 위한 극저온 냉동기 개발도 중요하지만 냉각판(cryoarray)에 최대한 많은 분자를 포획시키는 것 또한 최우선적으로 고려되어야 할 사항 중 하나이다. 이에 본 논문은 크라이오펌프용 냉각판의 기체분자 포획능력에 대하여 연구하였다. 냉각판의 분자포획능력의 해석은 형상계수법(view factor method)을 이용해 수행하였다. 해석에 이용한 냉각판은 현재 상용화된 모델들 중 원형 중앙판에 45$^{\circ}$ 하향 skirt가 달린 형태이며 8장의 냉각판이 일정한 간격을 두고 아래쪽으로 적층되어있고 이를 기본 모델로 하여 skirt의 형상이 다른 3장의 냉각판을 가진 네 가지 모델을 해석하였다. 해석에 이용한 냉각판의 기체분자 포획능력이 구속된 형상에서 얼마나 우수한가를 알아보기 위해 크라이오펌프의 입구 직경과 냉각판 중앙 원판의 직경비, 냉각판 사이의 거리, 그리고 skirt의 길이를 변화시켜가며 극저온 냉각판에 직접 응축되는 typeII가스와 흡착제가 도포된 부분에 의해 흡착되는 typeIII가스로 분류하여 해석을 수행하고 그 결과를 비교, 분석하였다. 크라이오펌프의 입구 직경과 냉각판 중앙 원판의 직경비가 증가함에 따라 typeII가스와 typeIII가스 모두 기체분자 포획능력이 증가하며 극저온 냉각판 사이 거리의 변화에 따른 기체분자 포획능력은 typeII가스의 경우 극저온 냉각판 사이의 거리가 증가할수록 증가한다. 하지만 typeIII가스는 모델 A, C의 경우 증가하고 모델 B, D의 경우 증가하다가 다시 약간 감소한다. skirt 길이 변화에 따른 기체분자 포획능력은 두 가스 모두 skirt 길이가 증가함에 따라 점점 급격하게 증가하고 모델 B, D는 나머지 두 모델에 비해 큰 값을 갖는다. 기체분자 포획능력을 해석한 결과를 실제 배기속도와 비교할 경우 절대적 수치로써의 비교는 어려우나 각 모델의 형상의 차이에 의한 상대적인 비교는 가능하다.

• Journal of the Korea Society of Computer and Information
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• v.13 no.6
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• pp.51-58
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• 2008

A version control system is used in a rapidly changed environment or a program which developed in a complicated environment. it is a problem of configuration thread in supporting information that we, in this method, can't know a exactly well-defined configuration rule information and a predefined information. In this paper. Library system is suggested, modelled, and implemented so as to configuration thread control the components required by the user in many ways. As for the library used in the configuration thread control suggested in this paper, the components can be retrieved from the library regardless of the infrastructure, applying the extended facet classification. This retrieval framework is managed using TreeSearch class and the configuration thread control function. The library system of this paper can be used by the interface with other languages, and this system is to have a advantage to extend a facet by user.

• Journal of the Society of Naval Architects of Korea
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• v.31 no.1
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• pp.50-62
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• 1994

This paper presents the results of a comparative analysis of the model test results to investigate the effect of bulbous bow installed on a large full form ship to the ship resistance performance. Seven parameters related to the shape of bulbous bow were selected and varied systematically to inquire their effects experimentally. A total number of twenty-three ship models with different bulbous bow were manufactured, and resistance tests. flow visualization test, and wave profile measurement were carried out for each model. For the comparative analysis between the various bulb forms and their model test results, bulbous bow forms are classified into nine groups according to their form characteristics. From the analysis of the trend of the resistance components, it was verified that form resistance has dominant effect on the total resistance of a slow full form ship. The model test and its statistical analysis showed that the direction of streamlines around bulbous bow has close relationship with resistance components. especially with form resistance

• The KIPS Transactions:PartB
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• v.9B no.4
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• pp.471-480
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• 2002

In this paper, we implemented a real-time system improving the performance of the paper currency discrimination by integrating a weighted region of interest matching algorithm with a weighted shape feature matching algorithm of the blocked image. The system classifies the paper currency by comparing a query image with compared images based on the database that contain images of paper currency. Especially, the system has good efficiency at the contaminated, rotated, and translated paper currency. The system hardware consists of three parts as follows : the paper currency image acquired by CIS(contact image sensor) is applied to the pre-processing part with A/D converter and PLD. Finally the pre-processed image data are classified by the main image processing part with a high-speed DSP based on the proposed algorithm.

• Journal of Korea Multimedia Society
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• v.9 no.9
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• pp.1131-1138
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• 2006

This paper proposes a novel method for grading of underground communication conduits by laser projection image analysis. The equipment thrust into conduit consists of a laser diode, a light emitting diode and a camera, the laser diode is utilized for generating projection image onto pipe wall, the light emitting diode for lighting environment and the image of conduit is acquired by the camera. In order to segment profile region, we used a novel color difference model and multiple thresholds method. The shape of profile ring is represented as a minimum diameter and the Fourier descriptor, and then the pipe status is graded by the rule-based method. Both local and global features of the segmented ring shaped, the minimum diameter and the Fourier descriptor, are utilized, therefore injured and distorted pipes can be correctly graded. From the experimental results, the classification is measured with accuracy such that false alarms are less than 2% under the various conditions.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.2
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• pp.141-148
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• 2011

This study presents the optimal grouping technique of columns which groups together columns of similar shortening trends to improve the efficiency of column shortening compensation. Here, Kohonen's self-organizing feature map which can classify patterns of input data by itself with unsupervised learning was used as the optimal grouping algorithm. The Kohonen network applied in this study is composed of two input neurons and variable output neurons, here the number of output neuron is equal to the column groups to be classified. In input neurons the normalized mean and standard deviation of shortening of each columns are inputted and in the output neurons the classified column groups are presented. The applicability of the proposed algorithm was evaluated by applying it to the two buildings where column shortening analyses had already been performed. The proposed algorithm was able to classify columns with similar shortening trends as one group, and from this we were able to ascertain the field-applicability of the proposed algorithm as the optimal grouping of column shortening.

• Journal of The Geomorphological Association of Korea
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• v.21 no.4
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• pp.85-96
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• 2014

A waterfall is a channel unit with steep bedrock. No strict criteria for height, water volume, gradient to define waterfalls exist in Korea. The goal of our study is to classify waterfalls based on morphological forms which are the outcomes of developmental processes. The genesis of waterfall depends upon erosional properties of waterfall. The height, gradient, bedrock strength and stream power of waterfalls are regarded as the main factors, by which waterfalls can be classified. We find out that the most important factor for the development of waterfalls is joint system. Development of joint system varies depending on bedrocks. Flow directions and erosional types are decided by the density and direction of joint system in the bedrock, which also decide the height and gradient of stream bed. Joint type decides the gradients of the bed, gradient and height of waterfalls, therefore, decides morphological forms.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.2
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• pp.53-57
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• 2009

The dividing flow in an open channel has a number of distinctive characteristics. One of these is that the separation zone interacts with a secondary motion along the inner wall of a branch channel, generating sediment accumulation. To investigate this phenomenon, a two-dimensional numerical model based on the shallow-water equations, RMA2, which calculates water surface elevations and horizontal-velocity components, was used to analyze the dividing flow. The obtained numerical results fully coincide with the laboratory measurements reported by Hsu et al.(2002). For the analysis of the numerical results, a separation zone-discharge rate relationship was proposed. To reduce the size of a separation zone, the topographies of diagonal and curved edges were proposed, smoothly connecting the upstream corner to branch channel.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.82-82
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• 2017

현대농업에서 잡초를 조기에 제거하지 못할 경우 작물의 성장에 장애를 초래하므로 제초작업은 매우 중요하다. 최근 친환경 고품질 농산물에 대한 소비자의 관심과 고품질 농산물에 대한 가격 차별화 등으로 제초제를 사용하지 않은 친환경 재배가 주목을 받고 있다. 제초제는 농작물에 따라 분류가 되어있어 종류마다 효과가 다르고 사용방법이 종류에 따라 어떻게 사용되는지 알기가 쉽지 않아 이에 따른 피해 또한 무시 할 수 없다. 현재 상용화되어 있는 제초기는 굴곡이 있는 고랑의 잡초를 효율적으로 제거하기 어려워 밭작물 제초작업에 사용하기 부적합하다. 밭작물 재배 기간에 행해지는 고랑의 제초작업은 평지보다 더 많은 힘이 필요하고 일반적인 제초기로는 좋은 결과를 얻기 어렵다. 또한 제초 작업시 농작물 피해와 멀칭 비닐을 손상시키는 문제가 발생 하고 있다. 따라서 밭작물에 효율적인 잡초를 제거하기 위해 굴곡이 있는 지형의 잡초를 제거하기 위한 제초기 개발이 반드시 필요하다. 밭작물용 제초기를 개발하기 위해 굴곡이 있는 고랑의 잡초 제거가 가능한 제초날의 형상 설계가 우선되어야 하며, 고랑의 잡초제거를 위한 제초날 형상설계를 하기 위해 우리나라 주요 밭작물 재배지의 이랑 넓이, 고랑 깊이 및 고랑 폭을 조사 분석하였다. 조사 작물 대상은 양파, 마늘, 무, 배추, 고추, 당근, 감자 총 7가지 작물을 대상으로 조사하였으며, 각 작물들의 이랑 넓이와 고랑 깊이 및 폭의 평균치를 구하여 제초날 설계에 적용하고자 하였다. 범위가 있는 수치는 높은 수치를 기준으로 계산하였으며 고랑의 평균 폭은 34.2cm이고, 고랑의 평균 깊이는 22.1cm가 나타났다. 잡초를 효과적으로 제거하기 위해 제초날의 형상은 고랑의 크기 및 형태에 맞게 원형으로 설계를 하여야 한다. 형상 설계는 밭작물 고랑 평균직경 및 평균높이를 고려하고, 제초작업시 제초날이 작물 및 멀칭비닐의 손상 하지 않도록 하기 위해 직경은 고랑 평균 폭의 75% 정도 치수로 형상을 설계하고, 제초날 깊이는 고랑의 굴곡형태을 고려할 때 제초날 반경의 70%정도로 설계하여 원형제초날 폭 250mm, 제초날 깊이 87.5mm로 설계해야 할 것으로 분석 되었다.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.4
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• pp.53-59
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• 2009

The purpose of this research is particle shape evaluation of granular soil and aggregate using Digital Image Process(DIP). DIP is very useful to measure the roughness and particle shape of aggregates. Couple of aggregates, like standard sand, two different crushed stones, and two different marine aggregates, have been employed. Shape factor of two different marine aggregates is ranged 0.35 to 0.54. Crushed stone I is that of 0.74 which is highly flat, but standard sand is elongated shape. Especially, two marine aggregate showed a big difference of width and length which meaned a long shape. There is any significant difference of elongation ratio and flakiness for each aggregate with different measuring system, like direct measurement of vernier calipers and DIP method. Within the limited test results, DIP is one of useful to get the particle shape of aggregate with limitation of measuring errors and to apply the particle distribution curve.